Eliminate mtl dependency.

Author: Patrick Thomson

semantic.cabal

@@ -67,6 +67,7 @@ common dependencies
                      , streaming ^>= 0.2.2.0
                      , text ^>= 1.2.3.1
                      , these >= 0.7 && <1
+                     , transformers ^>= 0.5.6.2
                      , unix ^>= 2.7.2.2
                      , proto3-suite
                      , proto3-wire

src/Reprinting/Translate.hs

@@ -9,9 +9,7 @@ import           Control.Effect
 import           Control.Effect.Error
 import           Control.Effect.State
 import           Control.Monad
-import           Control.Monad.Trans
 import           Streaming
-import           Streaming.Prelude (yield)
 import qualified Streaming.Prelude as Streaming
 
 import           Data.Reprinting.Errors
@@ -26,14 +24,14 @@ type TranslatorC
 
 contextualizing :: Stream (Of Token) TranslatorC a
                 -> Stream (Of Fragment) TranslatorC a
-contextualizing s = Streaming.for s $ \case
-  Chunk source -> yield . Verbatim . Source.toText $ source
-  Element t -> case t of
-    Run f -> lift get >>= \c -> yield (New t c f)
-    _     -> lift get >>= yield . Defer t
-  Control ctl -> case ctl of
-    Enter c -> lift (enterScope c)
-    Exit c  -> lift (exitScope c)
+contextualizing = Streaming.mapMaybeM $ \case
+  Chunk source -> pure . Just . Verbatim . Source.toText $ source
+  Element t -> Just <$> case t of
+    Run f -> get >>= \c -> pure (New t c f)
+    _     -> get >>= pure . Defer t
+  Control ctl -> Nothing <$ case ctl of
+    Enter c -> enterScope c
+    Exit c  -> exitScope c
     _       -> pure ()
 
 enterScope :: (Member (State [Scope]) sig, Carrier sig m)

src/Tags/Tagging.hs

@@ -10,10 +10,8 @@ import Prologue hiding (Element, hash)
 
 import           Control.Effect as Eff
 import           Control.Effect.State
-import           Control.Monad.Trans
 import           Data.Text as T hiding (empty)
 import           Streaming
-import           Streaming.Prelude (yield)
 import qualified Streaming.Prelude as Streaming
 
 import           Data.Blob
@@ -37,23 +35,22 @@ runTagging blob symbolsToSummarize
 
 type ContextToken = (Text, Maybe Range)
 
--- PT TODO: fix me as well
 contextualizing :: ( Member (State [ContextToken]) sig
                    , Carrier sig m
                    )
                 => Blob
                 -> [Text]
                 -> Stream (Of Token) m a
                 -> Stream (Of Tag) m a
-contextualizing Blob{..} symbolsToSummarize s = Streaming.for s $ \case
-  Enter x r -> lift (enterScope (x, r))
-  Exit  x r -> lift (exitScope (x, r))
-  Iden iden span docsLiteralRange -> lift (get @[ContextToken]) >>= \case
+contextualizing Blob{..} symbolsToSummarize = Streaming.mapMaybeM $ \case
+  Enter x r -> Nothing <$ enterScope (x, r)
+  Exit  x r -> Nothing <$ exitScope (x, r)
+  Iden iden span docsLiteralRange -> get @[ContextToken] >>= pure . \case
     ((x, r):("Context", cr):xs) | x `elem` symbolsToSummarize
-      -> yield $ Tag iden x span (fmap fst xs) (firstLine (slice r)) (slice cr)
+      -> Just $ Tag iden x span (fmap fst xs) (firstLine (slice r)) (slice cr)
     ((x, r):xs) | x `elem` symbolsToSummarize
-      -> yield $ Tag iden x span (fmap fst xs) (firstLine (slice r)) (slice docsLiteralRange)
-    _ -> pure ()
+      -> Just $ Tag iden x span (fmap fst xs) (firstLine (slice r)) (slice docsLiteralRange)
+    _ -> Nothing
   where
     slice = fmap (stripEnd . Source.toText . flip Source.slice blobSource)
     firstLine = fmap (T.take 180 . fst . breakOn "\n")